Molindone is a weak base, exhibiting greater solubility (FIG. 1) in acidic to slightly acidic media than in neutral to slightly alkaline pH values (i.e., the physiologic pH range of the gastro-intestinal tract). As a weakly basic drug, molindone is typically included into formulations in the form of a salt, such as chloride, sulfate, phosphate, monohydrogenphosphate, dihydrogenphosphate, bromide, iodide, acetate, propionate, decanoate, caprylate, formate, oxalate, malonate, succinate, fumarate, maleate, citrate, lactate, tartrate, methanesulfonate, mandelate, and the like.
Molindone hydrochloride, a medium potency antipsychotic, was marketed as Moban® for the management of schizophrenia in adults. Moban is an immediate release (IR) tablet formulation provided at the dose strengths of 5 mg, 10 mg 25 mg, 50 mg and 100 mg. As an IR dosage form it is taken 3 to 4 times daily with a typical maintenance dose range of 50 mg-100 mg per day. Limited molindone pharmacokinetic (PK) data is available in the literature. The drug substance has a reported bioavailability of 60%-70% relative to an intramuscular (IM) dose. It is absorbed rapidly following oral administration with a tmax observed between 1 to 1.5 hours. The drug substance is extensively and rapidly metabolized with an oral dose plasma elimination half-life of about 2 hours.